Habitat Suitability of Lapnisan (Aquilaria spp.) Under Various Climatic Projections for Reforestation in Negros Oriental, Philippines

Aim: This study aimed to assess the habitat suitability of Aquilaria species in Negros Oriental, Philippines, in response to projected climate change scenarios Representative Concentration Pathway (RCP) 2.6 and RCP 8.5 in 2050.Specifically, it sought to determine the area (km 2 ) and location for suitable Aquilaria reforestation sites. Methodology:The study employed purposive sampling and data mining to determine the actual location of Aquilaria species.The coordinates of Aquilaria were used to evaluate the model's performance through the Area Under the Curve (AUC), assessing its ability to distinguish between suitable and unsuitable habitats.Key input layers-including climatic variables (temperature and rainfall), environmental factors (land cover, soil type, elevation, and slope), and a Digital Elevation Model (DEM)-were reclassified and weighted based on their relevance to Aquilaria growth.These layers were integrated in ArcGIS to generate habitat suitability maps under climate scenarios RCP 2.6 and RCP 8.5, projecting potential suitable areas for Aquilaria by the year 2050.Results: Under the extreme RCP 8.5 scenario, no areas remained classified as highly suitable.However, moderately suitable habitats expanded significantly from 6.79% to 4,559.329km 2 (93.44%), while marginally suitable areas increased from 3.20 km 2 (0.06%) to 319.90 km 2 (6.56%).Despite a reasonably strong model performance (AUC = 0.79), ecological compatibility for Aquilaria declined-likely due to its dependence on stable moisture conditions and limited thermal tolerance.Additionally, habitat fragmentation and reduced connectivity, particularly in climate-impacted barangays, exacerbate risks to the species' survival.Conclusion: Highly suitable areas may vanish entirely, with the species being forced into less favorable, moderately to marginally suitable zones.The RCP 8.5 climate scenario marks a critical ecological turning point for Aquilaria spp., with suitable habitats in Negros Oriental projected to shift from low elevations (<300-400 m) to mid elevations (600-900 m), particularly under this high-emissions pathway.